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Greenhouse-gas versus aerosol forcing and African climate response

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Abstract

There are many indicators that human activity may change climate conditions all around the globe through emissions of greenhouse gases. In addition, aerosol particles are emitted from various natural and anthropogenic sources. One important source of aerosols arises from biomass burning, particularly in low latitudes where shifting cultivation and land degradation lead to enhanced aerosol burden. In this study the counteracting effects of greenhouse gases and aerosols on African climate are compared using climate model experiments with fully interactive aerosols from different sources. The consideration of aerosol emissions induces a remarkable decrease in short-wave solar irradiation near the surface, especially in winter and autumn in tropical West Africa and the Congo Basin where biomass burning is mainly prevailing. This directly leads to a modification of the surface energy budget with reduced sensible heat fluxes. As a consequence, temperature decreases, compensating the strong warming signal due to enhanced trace gas concentrations. While precipitation in tropical Africa is less sensitive to the greenhouse warming, it tends to decrease, if the effect of aerosols from biomass burning is taken into account. This is partly due to the local impact of enhanced aerosol burden and partly to modifications of the large-scale monsoon circulation in the lower troposphere, usually lagging behind the season with maximum aerosol emissions. In the model equilibrium experiments, the greenhouse gas impact on temperature stands out from internal variability at various time scales from daily to decadaland the same holds for precipitation under the additional aerosol forcing. Greenhouse gases and aerosols exhibit an opposite effect on daily temperature extremes, resulting in an compensation of the individual responses under the combined forcing. In terms of precipitation, daily extreme events tend to be reduced under aerosol forcing, particularly over the tropical Atlantic and the Congo basin. These results suggest that the simulation of the multiple aerosol effects from anthropogenic sources represents an important factor in tropical climate change, hence, requiring more attention in climate modelling attempts.

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References

  • Benkovitz CM, Easter RC, Nemesure S, Wagener R, Schwartz SE (1994) Sulfate over the North Atlantic and adjacent continental regions—evaluation for October and November 1986 using a 3-dimensional model driven by observation-derived meteorology. J Geophys Res 99:20725–20756

    Article  Google Scholar 

  • Benson C, Clay EJ (1998) The impact of drought on sub-Saharan economies. World Bank Tech Paper, No. 401, World Bank, Washington

  • Bird MI, Cali JA (1998) A million-year record of fire in sub-Saharan Africa. Nature 394:767–769

    Article  Google Scholar 

  • Chang P, Saravanan R, Ji L, Hegerl GC (2000) The effect of local sea surface temperature on atmospheric circulation over the tropical Atlantic sector. J Climate 13:2195–2216

    Article  Google Scholar 

  • Changnon SD (2003) Measures of economic impacts of weather extremes. Bull Am Meteorol Soc 84:1231–1235

    Article  Google Scholar 

  • Cooke WF, Liousse H, Cachier H, Feichter J (1999) Construction of a 1° × 1° fossil fuel emission dataset for carbonaceous aerosols and implementation into the ECHAM4 model. J Geophys Res 104:22137–22162

    Article  Google Scholar 

  • Cullen HM, de Menocal PB (2000) North Atlantic influence on Tigris-Euphrates streamflow. Int J Climatol 20:853–863

    Article  Google Scholar 

  • Desanker PV, Justice CO (2001) Africa and global climate change: Critical issues and suggestions for further research and integrated assessment modeling. Clim Res 17:93–103

    Article  Google Scholar 

  • Feddema JJ, Freire S (2001) Soil degradation, global warming and climate impacts. Climate Res 17:209–216

    Article  Google Scholar 

  • Feichter J, Roeckner E, Lohmann U, Liepert BG (2004) Nonlinear aspects of the climate response to greenhouse gas and aerosol forcing. J Climate 17:2384–2398

    Article  Google Scholar 

  • Findley SE (1994) Does drought increase migration? A study of migration from rural Mali during the 1983–1985 drought. Int Migr Rev 28:539–553

    Article  PubMed  Google Scholar 

  • Fowler HJ, Kilsby CG (2003) Implications of changes in seasonal and annual extreme rainfall. Geophys Res Let. DOI 30:10.1029/2003GL017327

  • Ginoux P, Chin M, Tegen I, Prospero JM, Holben B, Dubovik O, Lin SJ (2001) Sources and distributions of dust aerosols simulated with the GOCART model. J Geophys Res 106:20255–20273

    Article  Google Scholar 

  • Hastenrath S (2000) Interannual and longer term variability of upper-air circulation over the tropical Atlantic and West Africa in boreal summer. Int J Clim 20:1415–1430

    Article  Google Scholar 

  • Hennessy KJ, Gregory JM, Mitchell JFB (1997) Changes in daily precipitation under enhanced greenhouse conditions. Climate Dyn 13:667–680

    Article  Google Scholar 

  • Hosking JRM (1990) L-moments: Analysis and estimation of distributions using linear combinations of order statistics. J R Stat Soc B 52:105–124

    Google Scholar 

  • Houghton JT, Ding Y, Griggs DJ, Noguer M, Van der Linden PJ, Dai X, Maskell K, Johnson CA (eds) (2001) Climate change 2001. The Scientific Basis, Cambridge

    Google Scholar 

  • Hulme M, Doherty R, Ngara T, New M, Lister D (2001) African climate change: 1900–2100. Clim Res 17:145–168

    Article  Google Scholar 

  • Iacobellis SF, Frouin R, Somerville RCJ (1999) Direct climate forcing by biomass-burning aerosols: Impact of correlations between controlling variables. J Geophys Res 104:12031–12045

    Article  Google Scholar 

  • Jacobson MZ (2004) The short-term cooling but long-term warming due to biomass burning. J Climate 17:2909–2926

    Article  Google Scholar 

  • Jenkins GS, Kamga A, Garba A, Diedhiou A, Morris V, Joseph E (2002) Investigating the West African climate system using global/regional climate models. Bull Am Meteorol Soc 83:583–595

    Article  Google Scholar 

  • Jones C, Mahowald N, Luo C (2003) The role of Easterly Waves on African desert dust transport. J Climate 16:3617–3628

    Article  Google Scholar 

  • Kharin VV, Zwiers FW (2000) Changes in extremes in an ensemble of transient climate simulations with a coupled atmosphere-ocean GCM. J Climate 13:3760–3788

    Article  Google Scholar 

  • Kiehl JT, Briegleb BP (1993) The relative roles of sulfate aerosols and greenhouse gases in climate forcing. Science 260:311–314

    Article  Google Scholar 

  • Langner J, Rodhe H (1991) A global- three-dimensional model of the tropospheric sulfur cycle. J Atmos Chem 13:225–263

    Article  Google Scholar 

  • Li F, Vogelmann AM, Ramanathan V (2004) Saharan dust aerosol radiative forcing measured from space. J Climate 17:2558–2571

    Article  Google Scholar 

  • Liepert BG, Feichter J, Lohmann U, Roeckner E (2004) Can aerosols spin down the water cycle in a warmer and moister world? Geophys Res Let. DOI 31:10.1029/2003GL019060

  • Liousse C, Penner JE, Chuang C, Walton JJ, Eddleman H, Cachier H (1996) A global three-dimensional model study of carbonaceous aerosols. J Geophys Res 101:19411–19432

    Article  Google Scholar 

  • Lohmann U, Feichter J (2002) Can the direct and semi-direct aerosol effect compete with the indirect effect on a global scale? Geophys Res Let 28:159–162

    Article  Google Scholar 

  • Lohmann U, Feichter J (2004) Global indirect aerosol effects: a review. Atmos Chem Phys Discuss 4:7561–7614

    Article  Google Scholar 

  • Lohmann U, Feichter J, Chuang CC, Penner JE (1999) Predicting the number of cloud droplets in the ECHAM GCM. J Geophys Res 104:9169–9198

    Article  Google Scholar 

  • Lohmann U, Feichter J, Penner JE, Leaitch R (2000) Indirect effect of sulfate and carbonaceous aerosols: a mechanistic treatment. J Geophys Res 105:12193–12206

    Article  Google Scholar 

  • McGuffie K, Henderson-Sellers A, Holbrook N, Kothavala Z, Balachova O, Hoekstra J (1999) Assessing simulations of daily temperature and precipitation variability with global climate models for present and enhanced greenhouse climates. Int J Climatol 19:1–26

    Article  Google Scholar 

  • Monahan EC, Spiel DE, Davidson KL (1986) A model of marine aerosol generation via whitecaps and wave disruption. In: Monahan EC, McNiocaill G (eds) Oceanic whitecaps. D. Reidel Publishing Company

  • Myhre G, Grini A, Haywood JM, Stordal F, Chatenet B, Tanré D, Sundet JK, Isaksen ISA (2003 Modeling the radiative impact of mineral dust during the Saharan Dust Experiment (SHADE) campaign. J Geophys Res. DOI 108:10.1029/2002JD002566

  • Nicholson SE (2001) Climatic and environmental change in Africa during the last two centuries. Climate Res 17:123–144

    Article  Google Scholar 

  • Nicholson SE, Palao IM (1993) A re-evaluation of rainfall variability in the Sahel. Part I. Characteristics of rainfall fluctuations. Int J Climatol 13:371–389

    Article  Google Scholar 

  • Nicholson SE, Some B, and Kone B (2000) An analysis of recent rainfall conditions in West Africa, including the rainy season of the 1997 El Niño and the 1998 La Niña years. J Climate 13:2628–2640

    Article  Google Scholar 

  • Paeth H (2004) Key factors in African climate change evaluated by a regional climate model. Erdkunde 58:290–315

    Article  Google Scholar 

  • Paeth H, Hense A (2004) SST versus climate change signals in West African rainfall: 20th century variations and future projections. Climatic Change 65:179–208

    Article  Google Scholar 

  • Paeth H, Stuck J (2004) The West African dipole in rainfall and its forcing mechanisms in global and regional climate models. Mausam 55:561–582

    Google Scholar 

  • Penner JE, Dong X, Chen Y (2004) Observational evidence of a change in radiative forcing due to the indirect aerosol effect. Nature 427:231–234

    Article  PubMed  Google Scholar 

  • Prospero JM, Lamb PJ (2003) African droughts and dust transport to the Carribean: climate change implications. Science 302:1024–1027

    Article  PubMed  Google Scholar 

  • Ramanathan V, Crutzen PJ, Kiehl JT, Rosenfeld D (2001) Aerosols, climate and the hydrological cycle. Science 294:2119–2124

    Article  PubMed  Google Scholar 

  • Ramanathan V, Crutzen PJ, Mitra AP, co-workers (2002) The Indian Ocean experiment and the Asian brown cloud. Curr Sci India 83:947–955

    Google Scholar 

  • Roeckner E, Arpe K, Bengtsson L, Christoph M, Claussen M, Dümenil L, Esch M, Giorgetta M, Schlese U, Schulzweida U (1996) The atmospheric general circulation model ECHAM-4: Model description and simulation of present-day climate. Max-Planck-Inst. f. Meteor., Report No. 218. Hamburg

  • Roeckner E, Bengtsson L, Feichter J, Lelieveld J, Rodhe H (1999) Trensient climate change simulations with a coupled atmospherie-ocean GCM including the tropospheric sulfur cycle. J Climate 12:3004–3032

    Article  Google Scholar 

  • Rotstayn LD, Lohmann U (2002) Tropical rainfall trends and the indirect aerosol effect. J Climate 15:2103–2116

    Article  Google Scholar 

  • Saha K, Saha S (2001) African monsoons. Part I: climatological structure and circulation. Mausam 52:479–510

    Google Scholar 

  • Schnitzler KG, Knorr W, Latif M, Bader J, Zeng N (2001) Vegetation feedback on Sahelian rainfall variability in a coupled climate land-vegetation model. Max-Planck-Inst. f. Meteor., Report No. 329. 13pp

  • Schönwiese CD (1992) Praktische Statistik für Meteorologen und Geowissenschaftler. Stuttgart, Berlin

    Google Scholar 

  • Stier P, Feichter J, Kinne S, Kloster S, Vignati E, Wilson J, Ganzeveld L, Tegen I, Werner M, Balkanski Y, Schulz M, Boucher O (2004) The aerosol-climate model ECHAM5-HAM. Atmos Chem Phys Discuss 4:5551–5623

    Article  Google Scholar 

  • von Storch H, Zwiers FW (1999) Statistical analysis in climate research. Cambridge University Press, Cambridge, p 484

    Google Scholar 

  • Tansey K, Grégroire JM, Stroppiana D, Sousa A, Silva J, Pereira JMC, Boschetti L, Maggi M, Brivio PA, Fraser R, Flasse S, Ershov D, Binaghi E, Graetz D, Peduzzi P (2004) Vegetation burning in the year 2000: global burned area estimates from SPOT VEGETATION data. J Geophys Res. DOI 109:10.1029/2003JD003598

  • Tiedtke M (1989) A comprehensive mass flux scheme for cumulus parameterization in large scale models. Mon Wea Rev 117:1779–1800

    Article  Google Scholar 

  • Tselioudis G, DelGenio AD, Kovari W, Yao MS (1998) Temperature dependence of low cloud optical thickness in the GISS GCM: contributing mechanisms and climate implications. J Climate 11:3268–3281

    Article  Google Scholar 

  • Ulbrich U, Christoph M (1999) A shift of the NAO and increasing storm track activity over Europe due to anthropogenic greenhouse gas forcing. Climate Dyn 15:551–559

    Article  Google Scholar 

  • Ward MN (1998) Diagnosis and short-lead time prediction of summer rainfall in tropical North Africa at interannual and multi-decadal time scales. J Climate 11:3167–3191

    Article  Google Scholar 

  • Zeng N, Neelin JD (2000) The role of vegetation-climate interaction and interannual variability in shaping the African Savanna. J Climate 13:2665–2670

    Article  Google Scholar 

  • Zolina O, Kapala A, Simmer C, Gulev S (2004) Analysis of extreme precipitation over Europe from different reanalyses: A comparative assessment. Global Planet Change 44:129–161

    Article  Google Scholar 

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Acknowledgements

This work was supported by the Federal German Minister of Education and Research (BMBF) under grant No. 07 GWK 02 and by the Ministry of Science and Research (MWF) of the Federal State of Northrhine-Westfalia under grant No. 223-21200200.

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Paeth, H., Feichter, J. Greenhouse-gas versus aerosol forcing and African climate response. Clim Dyn 26, 35–54 (2006). https://doi.org/10.1007/s00382-005-0070-z

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